Influence of drought, high temperatures, and/or defense against arthropod herbivory on the production of secondary metabolites in maize plants. A review

Maize crops are exposed to a wide range of abiotic and biotic stresses, which induce the disruption of plant metabolism and affect crop yield and quality. An increase in drought or heat stress periods has been reported as a direct consequence of global climate change. These abiotic conditions can increase and promote populations of herbivorous arthropods on maize plants. Plants generally show the ability to adapt to stressful conditions through the production of secondary metabolites (SM). This review aimed to summarize the influence of the combination of abiotic stresses, such as drought and high temperatures, and biotic stress, such as the attack of pest arthropods, on the production of SM in maize crops. In this manuscript, we focus on how individual or combined stress factors affect the accumulation of SM in maize plants. Furthermore, we discuss the importance of metabolomics in the detection and/or quantification of primary and secondary stress-responsive metabolites and understand how these metabolic networks are regulated. We also explain the role of plant hormones (abscisic acid, salicylic acid, jasmonic acid, and ethylene) in the interaction with plant tolerance and systemic-acquired resistance to multiple stresses in maize. In conclusion, this review provides information on how SM participate in biotic and abiotic responses via biochemical and transcriptional factors involved in maize stress tolerance.